WHAT IS RENEWABLE ENERGY?
On this blog we often talk about the ecological transition, focusing on recycling, innovative green materials and how to reduce the impact of producing the things we use every day.
However, in order to explore some aspects of the circular economy, we need to ask ourselves a question: what is the best way to produce energy in a sustainable economy?
To answer this question, we have to start from the premise that there is no way to produce energy without creating some level of carbon dioxide emissions or solid or gaseous pollutants.
However, there is a huge difference between one source and another. In order to estimate these values, international organisations such as the IEA (International Energy Agency) assign each energy source a value called carbon intensity. This value measures how much CO2 is emitted for each kWh [*1] produced over the entire life cycle of a facility, from the construction of a power plant to its complete disposal, throughout its operating life.
Analysis of the data shows, for example, that each kWh of electricity produced by a coal-fired power station emits 954 grCO2eq [*2], while the same kWh produced by a hydroelectric power station emits 11 grCO2eq!
Quite a difference, don’t you think?
That is why when we talk about hydroelectric, photovoltaic, wind and geothermal energy, we are talking about LOW CARBON or low CO2 energy sources.
In addition to being low carbon, these energy sources are also RENEWABLE, i.e. the electricity generation process is not based on the combustion of a fossil fuel, which is finite on earth, but uses energy from the sun, the wind, the oceans or the earth’s heat, which can be defined as infinite from a human perspective.
But beware, there are two clarifications to be made. Firstly, not all renewables are low-carbon; for example, biomass, i.e. wood pellets, but also power plants that burn vegetable waste, etc., are renewable but not low-carbon. On the contrary, nuclear fission energy is very low in emissions (5 gr CO2eq) but is not renewable because uranium is a finite mineral.
Having made this introduction, in the following episodes we will look in detail at the merits and shortcomings of the best renewable technologies available today!
[1] kWh is a unit of energy. 1 kWh is the equivalent of the energy consumed by a 1000W household appliance running for one hour. [2] grCO2eq, stands for grams of carbon dioxide equivalent and is a unit of measurement used to estimate the greenhouse effect of a production process, means of transport, etc. As there are many greenhouse gases, of which CO2 is the best known, it is preferable to make equivalences with CO2 in order to simplify greenhouse calculations. For example, methane is 85 times more powerful than CO2, so one gram of methane emitted into the atmosphere is equivalent to 85 grams of CO2eq.Sources:
https://www.iea.org/reports/global-energy-review-co2-emissions-in-2021-2https://www.eea.europa.eu/ims/greenhouse-gas-emission-intensity-of-1
